Potential of Line Charge

The potential of a line of charge can be found by superposing the point charge potentials of infinitesmal charge elements. It is an example of a continuous charge distribution.

Potential for Ring of Charge

The potential of a ring of charge can be found by superposing the point charge potentials of infinitesmal charge elements. It is an example of a continuous charge distribution. The ring potential can then be used as a charge element to calculate the potential of a charged disc.

Since the potential is a scalar quantity, and since each element of the ring is the same distance r from the point P, the potential is simply given by 由于电势是一个标量量，且环上每个元素到点P的距离都是r，因此电势 simply 由下式给出。 If the charge is characterized by an area density and the ring by an incremental width dR', then: 如果电荷由面积密度表示，而环则由微小宽度dR'表示，那么：

In this form it could be used as a charge element for the determining of the potential of a disc of charge.

Potential for Disc of Charge

The potential of a disc of charge can be found by superposing the point charge potentials of infinitesmal charge elements. It is an example of a continuous charge distribution. The evaluation of the potential can be facilitated by summing the potentials of charged rings. The integral over the charged disc takes the form: